From a sales standpoint, robot vacuums are the most successful consumer robot ever. Robot vacuums have certainly simplified, not quite eliminated, one of the most daunting household chores: cleaning. So the success makes sense.

But just how popular are robot vacuums? At TechCrunch Beijing, iRobot CEO Colin Angle said 20 percent of the world’s vacuum cleaners are robots. Of those that are robots, 70 percent are from iRobot, which has sold 14 million Roombas to date.

As Angle said, iRobot “has a long lead in terms of working on the problem, and because it’s focused on consumer home cleaning products exclusively.” iRobot was built on military robotics, of course, but it divested that division for $45 million in early 2016 after being pressured by investors.